River flood risk is increasing: what are the best adaptation measures to protect lives and save assets?
New research co-developed by scientists from the Joint Research Centre of the European Commission and published in Nature Climate Change compares the costs and benefits of flood risk reduction measures in Europe.
The study estimates that in the European Union and UK river flooding currently causes annual damage of about €7.6 billion and exposes around 160 000 people/year to inundation. In a 3°C global warming scenario and without climate change adaptation, flood damage in Europe would rise to €44 billion per year, exposing nearly half a million Europeans every year until the end of the century.
As a result, flood adaptation is crucial to offset rising river flood risk in Europe with climate change and scientists point out it can be cost-effective. Creating water detention areas, building river dykes, floodproofing buildings, and relocating people and assets are key flood adaptation measures. These measures can considerably lower projected flood losses in Europe until 2100 in all the 3 scenarios of global warming - 1,5°C, 2°C and 3°C - assessed.
A combination of different measures optimised at the level of river basins are likely the best way to maximise local benefits and minimise the drawbacks of each action. Reducing flood peaks using detention areas is economically the most attractive option: each euro invested would save four euro in avoided damages (in a 3°C warming scenario).
Strengthening existing dyke systems is also cost-effective in most countries of Europe, but with considerable variation between countries in risk reduction potential and cost-benefit ratios. Despite being less economically attractive, adaptation through building floodproofing and relocation can help reduce impacts in areas frequently hit by floods, or with a high concentration of people or valuable goods.